Anchored polymerase chain reaction (PCR) will be used to isolate and amplify the T cell receptor (TCR)-alpha and beta genes expressed by a panel of myelin basic protein (MBP)-specific human T cell clones derived from patients with multiple sclerosis (MS) and controls. T cell clones that have previously been generated, and new clones to be isolated from peripheral blood, will be assayed for epitope specificity on the MBP molecule. Genetic (HLA) restriction studies will be performed to determine which major histocompatibility complex determinants govern antigen recognition by the clones. The MS and control populations will be selected to include subjects with varied HLA haplotypes and ethnic backgrounds. The amplified genes will be sequenced in order to identify the utilized V- alpha (Valpha), Jalpha, V-beta (VB), DB, and JB gene segments and junctional residues. TCR gene segment usage will be correlated with epitope specificity and HLA restriction patterns exhibited by the T cell clones. Potential disease-specific correlations will also be evaluated. When previously undescribed TCR gene segments, or predominant use of known gene segments, are detected, a rapid initial determination will be made with regard to the disease-specificity of the finding. This will be accomplished by performing anchored PCR on cDNA derived from peripheral blood lymphocyte preparations obtained from large populations of MS patients and controls. The amplified material will be screened with oligonucleotides specific for the gene segment in question or with cDNA from the T cell clones that expressed the gene segment. The results will be used to determine the feasibility of proceeding with clinical trials in which MS patients are treated with regimens designed to inhibit immune responses mediated by specific TCR-V, D, or J gene segments in an effort to specifically suppress the immune response to MBP. Such a therapeutic approach would be encouraged by a finding of restricted heterogeneity of TCR gene segment usage. Alternatively, if a great degree of TCR heterogeneity is found, T cell vaccination is likely to provide a more reasonable approach to the suppression of MBP-specific T cell responses in vivo.